<!DOCTYPE HTML>
<script src="../../../resources/testharness.js"></script>
<script src="../../../resources/testharnessreport.js"></script>
<script src="../../../resources/gesture-util.js"></script>
<script src="../../../virtual/percent-based-scrolling/resources/percent-based-util.js"></script>
<style>
#targetDiv {
  width: 200px;
  height: 200px;
  overflow: scroll;
}

#innerDiv {
  width: 400px;
  height: 400px;
}
</style>

<body style="margin:0">
<div id="targetDiv">
  <div id="innerDiv">
  </div>
</div>
</body>

<script>
if (window.internals)
  internals.runtimeFlags.overscrollCustomizationEnabled = true;

var target_div = document.getElementById('targetDiv');
var rect = target_div.getBoundingClientRect();
var x = rect.left + rect.width / 2;
var y = rect.top + rect.height / 2;

// SPEED_INSTANT doesn't work here because tests are timing out.
// This could actually be a bug in how the overscroll event is computed.
// Possible explanation on what happens is that "leftover" delta from a single
// event doesn't cause an overscroll event, only when the next event arrives
// and the full delta is overscroll do we dispatch the event.
// When the speed is INSTANT we'll put the entire scrolling delta into a single
// event so we don't generate an overscroll event in that case.
const pixelsPerSec = 2000;
const pixelsToScroll = 600;
const { x: pixelsToScrollX, y: pixelsToScrollY } = calculatePixelsToScroll(
  target_div, pixelsToScroll, pixelsToScroll
);

var overscrolled_x_delta = 0;
var overscrolled_y_delta = 0;
function onOverscroll(event) {
  assert_false(event.cancelable);
  // overscroll events are bubbled when the target node is document.
  assert_true(event.bubbles);
  overscrolled_x_delta = event.deltaX;
  overscrolled_y_delta = event.deltaY;
}
document.addEventListener("overscroll", onOverscroll);

async function test_overscroll_event_fire(source_device,
    precise_scrolling_delta) {
  await waitForCompositorCommit();
  overscrolled_x_delta = 0;
  overscrolled_y_delta = 0;

  // Scroll up on target div and wait for the doc to get overscroll event.
  await smoothScroll(
    pixelsToScrollY, x, y, source_device, "up", pixelsPerSec,
    precise_scrolling_delta
  );
  await waitFor(() => { return overscrolled_y_delta < 0; },
      'Document did not receive overscroll event after scroll up on target.');
  assert_equals(target_div.scrollTop, 0);

  // Scroll left on target div and wait for the doc to get overscroll event.
  await smoothScroll(
    pixelsToScrollX, x, y, source_device, "left", pixelsPerSec,
    precise_scrolling_delta
  );
  await waitFor(() => { return overscrolled_x_delta < 0; },
      'Document did not receive overscroll event after scroll left on target.');
  assert_equals(target_div.scrollLeft, 0);
}

promise_test (async (t) => {
  // Make sure that no overscroll event is sent to target_div.
  target_div.addEventListener("overscroll",
      t.unreached_func("target_div got unexpected overscroll event."));
  return test_overscroll_event_fire(GestureSourceType.MOUSE_INPUT,
    false /* precise_scrolling_delta */);
}, 'Tests that the document gets overscroll event when no element scrolls ' +
    'after wheel scrolling in smooth-scrolling path.');

promise_test (async (t) => {
  // Make sure that no overscroll event is sent to target_div.
  target_div.addEventListener("overscroll",
      t.unreached_func("target_div got unexpected overscroll event."));
  return test_overscroll_event_fire(GestureSourceType.MOUSE_INPUT,
    true /* precise_scrolling_delta */);
}, 'Tests that the document gets overscroll event when no element scrolls ' +
    'after non-animated wheel scrolling.');

promise_test (async (t) => {
  // Make sure that no overscroll event is sent to target_div.
  target_div.addEventListener("overscroll",
      t.unreached_func("target_div got unexpected overscroll event."));
  return test_overscroll_event_fire(GestureSourceType.TOUCH_INPUT);
}, 'Tests that the document gets overscroll event when no element scrolls ' +
    'after touch scrolling.');
</script>
